The present invention generally relates to wood processing equipment and, more particularly, to an apparatus for stacking rows of elongated members to form bundles.
In typical sawmills, wherein raw wood is sawn mechanically into lumber pieces (i.e., planks, boards, etc.), much effort is spent in maximizing the productivity and output. Consequently, sawmills are increasingly automated in order to accelerate speed of execution of the various tasks in the manufacturing of lumber pieces.
In one such task, rows of lumber pieces abutted side by side are transferred from a conveyor to form bundles. In some cases, slats are disposed between stacked rows in order to allow air to circulate between rows for the drying of the lumber pieces. Rows of lumber pieces may also be stacked to form bundles for the packaging and shipping thereof, in which case slats separating the rows are not always required.
U.S. Pat. No. 4,290,723, issued on Sep. 22, 1981 to Johansson, discloses a timber package arranger which comprises two sets of arms in complementary operation. These sets of arms translate one after another in a cyclic motion, and are each mounted to inclinable ramps which control the inclination of the sets of arms. Accordingly, a first set of arms moving forward on an inclined path accumulates lumber pieces being discharged from a conveyor. Once the first set of arms has gathered a predetermined amount of lumber pieces to form a row of side-by-side abutted lumber pieces, it is lowered to a planar position while still moving forward toward and over a bundle of stacked lumber pieces. The first set of arms then translates rearwardly, whereby a stop member discharges the lumber pieces accumulated on the first set of arms, onto a bundle being formed. The second set of arms executes the same motions to transfer rows of lumber pieces from a conveyor to the bundle, but lags the first set of arms. While the first set of arms discharges its load on the bundle, the second set of arms accumulates lumber pieces from the conveyor, and vice versa. The two sets of arms operate in synchronism. Accordingly, the conveyor is constantly discharged from its lumber pieces.
U.S. Pat. No. 5,613,827, issued on Mar. 25, 1997 to Vande Linde, discloses a dual-arm lumber stacker assembly. The assembly comprises sets of parallel stacker arms for engaging and lifting rows of lumber pieces ranging between 8 to 20 feet onto a stack consisting of other rows of lumber pieces, in order to form a bundle. These sets of stacker arms are oriented parallel to the direction of movement of a conveyor, which conveys lumber pieces to the stacking apparatus. A set of stacker arms comprises at least two arms which are spaced so that each piece of lumber spans at least these two arms to be supported thereby. The stacker arms each have a rearward end carried by a drive chain extending between a pair of spaced sprockets. The forward end of the stacker arms is positioned to engage and lift rows of lumber pieces carried on the conveyor. These stacker arms are each pivotally supported generally at the middle thereof on a slide bearing which moves back and forth with the movement of the arms, which are driven by the drive chain. When the rearward ends are carried around the sprockets by the drive chain, the stacker arms are caused to pivot on the slide bearing, thereby causing the forward ends of the stacker arms to be elevated and lowered as the arms reach opposed positions on the drive chain.
Dual sets of arms in complementary motion are a xe2x80x9cmustxe2x80x9d in stacking apparatuses. However, further components of the stacking apparatuses may further be modified to adapt the stacking apparatuses for faster operating speeds and, consequently, maximized output and productivity.
It is a feature of the present invention to provide an apparatus for stacking rows of elongated members at a maximized speed.
It is a further feature of the present invention to provide a device for automatically disposing slats on selected rows of lumber pieces in conjunction with the above-mentioned apparatus.
According to the above feature of the present invention, and from a broad aspect thereof, the present invention provides an apparatus for transferring rows of side-by-side elongated members from a conveyor to a stacking platform to form bundles. The apparatus comprises a conveyor for conveying separate rows of the elongated members in a direction perpendicular to longitudinal axes of the elongated members. A plurality of parallel stacker arms are displaceable in a direction parallel to the conveying of the elongated members, between a retracted position, wherein the parallel stacker arms are positioned below the conveyor portion so as not to interfere with the elongated members being conveyed on the conveyor portion, and a stacking position, wherein the stacker arms are positioned above the stacking platform for disposing rows of elongated members thereon. Each stacker arm has a rear end connected to a carriage so as to pivot about the carriage. Each carriage is actuated so as to displace each stacker arm between the retracted position and the stacking position. Each stacker arm has a follower portion in operative contact with a ramp. The ramp is displaceable between an inclined position and a horizontal position, for guiding the pivoting of the stacker arms about the carriages, such that stacker arms moving from the retracted position to the stacking position are pivoted upward to pick up a row of elongated members from the conveyor portion, and that stackers arms moving from the stacking position to the retracted position are kept generally horizontal, so as to encompass the rows of elongated members conveyed on the conveyor portion. The plurality of stacker arms are divided in a first group of stackers arms and a second group of stacker arms. The first group of arms moves in concert from the retracted position to the stacking position so as to pick-up a row of elongated members being conveyed on the conveyor portion, while the second group of arms moves oppositely in concert from the stacking portion to the retracted portion, and vice-versa.
According to a further broad aspect of the present invention there is provided an apparatus for disposing slats between rows of a product being deposited on a bundle being formed. The apparatus comprises an outer shell portion defining a magazine for storing a stack of slats. The magazine is open at a bottom end thereof for slats to outlet therefrom. Pincer arms are pivotally mounted to the outer shell portion so as to be displaceable between a pincer arm supporting position and a pincer arm bypassing position. The pincer arm each have a finger projecting laterally from a bottom end thereof so as to block the open bottom end of the magazine when the pincer arms are in the pincer arm supporting position. A carriage is operatively mounted to the outer shell portion so as to translate vertically thereon. The carriage is adapted for being actuated in displacement between a carriage retracted position and a carriage discharging position. The carriage has transport arms pivotally mounted thereto. The transport arms each have a support surface portion projecting laterally from a bottom thereof. The support surface portions are positioned generally below the open bottom end of the magazine. Displacement of the carriage from the carriage discharging position to the carriage retracted position actuates the pincer arms into pivoting from the pincer arm supporting position to the pincer arm bypassing position, and back to the pincer arm supporting position, so as to dispense a bottommost slat from the stack of slats in the magazine onto the support surface portion of the transport arms. Displacement of the carriage from the carriage retracted position to the carriage discharging position causes the slat on the support surface portions to be disposed on the bundle being formed.